This is one of the coolest ideas ever! The adaptability is great, since you can move it from a commuter bike to a mountain bike and back.
Are there any issues with the fact that the bike is being pushed from the rear? Do you notice it on turns?
The trailer pretty much reacts the same as pulling any single wheel trailer. No real issues having the trailer acting as a power source pusher. The setup turns fine even with a surfboard attached. I have several electric bikes that I use in our Electric bike tour business, so I can make a comparison to them. While they certainly have their advantages, the Wattwagon has it's own in regards to versatility, being able to use any quality bike, storage capacity etc.
I think it really shines for touring since it allows you to haul more stuff, fight hills and headwinds and once you get to your destination to unhook and have a normal bike to ride around with or even mountain bike with.
You can either use it in throttle mode or pedal assist mode. I am liking the pedal assist mode (which is programmable) since it encourages pedaling, and extends the range. The throttle mode makes it more scooter like.
Last night I did my longest ride between charges ever. I rode to the trailhead, met some friends, did our regular mountain bike ride then rode home. 27 miles with over 3,000 feet of climbing and I still had 5 to 10 miles more battery left. This was with a 48 volt 15 amp hour battery.
Next week I plan on doing a 150 mile one day ride to Joshua tree. I will have two battery packs and recharge at lunch (around 75 miles). This will be my tuneup for a 400 mile tour I plan on doing before the end of the year.
If you are in the San Diego area I will be demoing the Wattwagon at the SDG&E electric bike seminar the evening of October 14th. If interested PM me and I will get you the information. Should be a fun evening. There will be plenty of other E-bikes there for demo too.